“I’ll break it again,” said Thomas, who finished with 19 points on just 4-of-21 shooting. “I’m not worried about it. I’ll break it.”

Thomas, the Eastern Conference’s leading scorer at 29.6 points per game, turned in his worst shooting performance of the season during Monday’s defeat. Playing against the same Hawks team that often frustrated him during Boston’s first-round playoff exit last season, Thomas couldn’t finish near the basket (3-of-13 at the rim) or loosen things up from the outside (1-of-7 beyond 12 feet).

“They didn’t do nothing special,” Thomas said. “It’s just I missed a lot of shots in the paint that I usually make. I got to where I wanted to. That wasn’t just me. It was our team. We missed a lot of shots that we usually make. And you just have to tip your hat off to the Atlanta Hawks.”

Thomas, who is averaging a league-best 10.4 points per game in the fourth quarter, scored just two points in the final frame on Monday. He was lifted with a little more than three minutes to go and the Hawks up by 20.

Isaiah Thomas’ streak of 20-point games came to an end Monday, when he made just 4 of 21 shots and scored just two points in the fourth quarter. Maddie Meyer/Getty Images

Celtics coach Brad Stevens noted he was unaware that Thomas fell short of his 20-point streak but marveled at his ability to consistently score points this season. Thomas has scored 18 points or more in every game this year.

“His consistency scoring the ball has been incredible,” Stevens said. “We’ve talked about that a lot. He’s had an incredible run at it and you’re going to have nights like that, that’s certainly the case. But you know, again, I think we should also credit Atlanta. I feel like Atlanta deserves to be credited for tonight. I thought they played great.”

Given Thomas’ mini funk — at least by his lofty standards this year — Stevens was asked if he’s concerned at all about Thomas’ shooting or the way his teammates look to him to shoulder the offense in key situations.

“I’m not as worried about Isaiah; I’m worried about how our team’s playing,” Stevens said.

Thomas was also uncharacteristically careless with the basketball, producing a team-high seven turnovers on a night the Celtics gave the ball away 18 times. Thomas did add seven rebounds and seven assists.

The Celtics have lost three of their past four games and sweated out Sunday’s win in Detroit. A visit from the defending champion Cleveland Cavaliers looms Wednesday.

Thomas acknowledged that he has set a high bar for himself during this 20-point streak but was OK with those expectations.

“That’s how it is when you want to be great,” said Thomas. “No, I’m not worried about it. One of those games. Like I said, what was it 40-something games [of 20 points or more]? I’ll break it. I’m not worried about the record.”

Even when Stephen Curry ties a mark for 3-point futility, the Warriors win.

Things always seem to be a little extra intense against Atlanta, especially after Hawks guard Dennis Schroder accused Thomas of talking ill of his family during Boston’s win in Atlanta in January. The two players were spotted chatting with each other early in Monday’s game but Thomas, who said after the previous meeting that he wouldn’t talk about Schroder any more and shot down his trash-talking claims, didn’t care to share what was said this time around.

Thomas appeared to inadvertently hit Atlanta’s Paul Millsap with an elbow while driving to the basket for his final bucket of the night. That didn’t sit well with the Hawks’ sideline but Thomas said he and Millsap quickly smoothed things over.

Hawks coach Mike Budenholzer said his team never could quite relax even as Thomas struggled with his shot.

“It’s one of those nights, Isaiah has been scoring at a really high clip,” Budenholzer said. “You can never relax when you’re guarding him. You need your bigs to be engaged. It was a little bit scary when he got to the free throw line to start the third quarter but, everyone that was on him was able to scramble out to shooter when he did pass.”

Thomas wouldn’t let a couple quiet nights bother him.

“[Monday] was just an off night for me. So you have those,” he said. “And then, when we played Toronto, they showed two or three guys. So I can’t run through the whole team. I’ll be all right. That’s what teams are game-planning to do.

“The whole world knows what time it is in the fourth quarter and they’re game-planning to stop me. I just have to figure it out. And I will.”